Siemens siprotec SJ62 User Manual page 240

Example
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
The following figure illustrates the control of the protective stages 50-2 and 50N-2.
Figure 2-83 Control of protection elements for two-fold, successful auto-reclosure
Before the first reclosure faults are to be eliminated quickly applying stages 50-2 or
50N-2. Fast fault termination thus has priority over selectivity aspects as the reclosing
action aims at maintaining normal system operation. If the fault prevails, a second trip-
ping is to take place instantaneously and subsequently, a second reclosure.
After the second reclosure, however, elements 50-2 or 50N-2 are to be blocked so the
fault can be eliminated applying elements 50-1 or 50N-1 according to the networks time
grading schedule giving priority to selectivity concerns.
Addresses 7202 bef.1.Cy:50-2, 7214 bef.2.Cy:50-2 and 7203
bef.1.Cy:50N-2 and 7215 bef.2.Cy:50N-2 are set to instant. T=0 to enable
the stages after the first reclosure. Addresses 7226 bef.3.Cy:50-2 and 7227
bef.3.Cy:50N-2, however, are set to blocked T=∞ to ensure that elements 50-2
and 50N-2 are blocked when the second reclosure applies. The back-up stages e.g.,
2.14 Automatic Reclosing System 79
238